string(JSON): fix error message on invalid mode
The GET_ARRAY and MEMBERS modes were removed during review in !5159 (comment 824244), but were accidentally left in an error message.
Topic-rename: string-JSON-error-modes
Edited by Brad King
The GET_ARRAY and MEMBERS modes were removed during review in !5159 (comment 824244), but were accidentally left in an error message.
Topic-rename: string-JSON-error-modes